TABLE 2.
Iron and inflammatory indicators in the third trimester of pregnancy overall and by prepregnancy BMI category1
| Prepregnancy BMI category | ||||
|---|---|---|---|---|
| Variable | Prepregnancy nonobese (n = 29) | Prepregnancy obese (n = 21) | Total (n = 50) | P value |
| Hb, g/dL | 11.0 ± 1.2 | 10.6 ± 1.4 | 10.8 ± 1.3 | 0.31 |
| Anemia,2 %, (n) | 35 (10) | 43 (9) | 56 (19) | 0.55 |
| Adjusted serum ferritin,3 μg/L, median (IQR) | 9.0 (9.0) | 14.2 (17.8) | 10.3 (11.9) | 0.12 |
| Adjusted serum ferritin <12 μg/L, %, (n) | 59 (17) | 48 (10) | 46 (23) | 0.44 |
| Serum iron, μg/dL | 63.1 ± 21.9 | 59.2 ± 19 | 61.5 ± 20.6 | 0.52 |
| Adjusted sTFR,3 nmol/L, median (IQR) | 29.5 (11.0) | 25.0 (8.8) | 28.3 (11.5) | 0.23 |
| Transferrin saturation, % | 12.9 ± 5.4 | 13.5 ± 5.4 | 13.2 ± 5.4 | 0.70 |
| Serum hepcidin, ng/mL | 20.5 ± 8.9 | 22.9 ± 8.0 | 21.5 ± 8.5 | 0.31 |
| Serum hs-CRP, mg/L, median (IQR) | 3.4 (3.4) | 8.5 (6.8) | 4.6 (6.6) | 0.0007 |
| Serum IL-6, pg/mL, median (IQR) | 1.5 (1.3) | 1.9 (1.8) | 1.7 (1.4) | 0.55 |
| Serum erythropoietin, mIU/mL | 30.8 ± 19.7 | 32.5 ± 12.3 | 31.5 ± 16.9 | 0.71 |
| Adjusted total body iron,3 mg/kg | 4.3 ± 2.6 | 6.0 ± 3.1 | 4.9 ± 2.9 | 0.04 |
| 57Fe utilization, %, median (IQR) | 11.2 (8.3) | 7.7 (8.9) | 9.8 (9.9) | 0.23 |
Values are means ± SDs, medians (IQRs), or % (n) unless otherwise indicated. The Student's t test was used for normally distributed variables, the Wilcoxon rank-sum test for nonnormally distributed continuous variables, and the chi-square test for categoric variables to analyze differences between the groups. All comparisons were nonsignificant at P > 0.05. Hb, hemoglobin; hs-CRP, high sensitivity C-reactive protein; sTFR, serum soluble transferrin receptor.
Hb <11.0 g/dL was used to indicate anemia in nonblack women and adjusted downward by 0.8 g/dL to 10.2 g/dL for black women per Institute of Medicine guidelines (30).
Adjusted using the BRINDA (Biomarkers Reflecting Inflammation and Nutritional Determinants of Anemia) correction factor methods (33–35).